In the art, it is generally known that to reduce inventory space or to increase the shelf life of certain drugs, or both, it is advantageous to reduce these drugs to a dry or powdered form. These dry or powdered drugs are normally stored in a sealed container such as a vial, and reconstituted into liquid form with an appropriate diluent or solvent solution prior to administration to a patient. The vials, typically formed of glass or plastic materials, include an elastomeric stopper sealing the open end of the vial. The stopper includes a portion inserted into the neck of the vial as well as a planar portion which rests on top of the vial, against the vial rim. The planar portion is normally tightly affixed to the vial rim with an aluminum crimp cap. Owing to the malleable nature of aluminum, the crimp cap readily adapts itself any differing dimension or tolerances which may exist between the stopper and the vial. The result is that the crimp cap evenly distributes sealing forces between the stopper and the vial. Thus, it has been generally recognized in the art that the vial/stopper/aluminum crimp cap solution safeguards the sterility of the drug contained within the vial over suitably long storage periods and prescribed conditions. The sizes and dimensions of the various vials and stopper components may be configured to given standards, such as given ISO standards.
One way to reconstitute the drug stored in the vial is to introduce the solvent or diluent from a syringe by piercing the stopper sealing the vial. Owing to various considerations, such as the convenience of the healthcare worker charged with reconstituting the drug, the art has recognized ways to transform the standard sealed vial into a system suitable for permitting safe, effective reconstitution of the drug contained within the vial. In these systems, typically, a fluid transfer assembly is connected to the neck of the vial. The fluid transfer system includes structure for connecting the vial to a source of diluent, such as diluent held in bottles, bags or syringes. The transfer assembly is thereafter activated to permit the flow of fluid into the vial to from the source of diluent, thereby reconstituting the drug.
In some configurations, the systems are such that standard vial stopper is eliminated in favor of fluid transfer assembly having a rubber stopper which is inserted into the neck of the vial, without the need for a planar portion which rests against the rim of the vial. This stopper remains within the neck until such time as reconstitution of the drug is desired. When the transfer assembly is activated, the stopper is urged towards the interior of the vial to open the neck, thereby permitting fluid to flow through the transfer assembly and into the vial body. Examples of such approaches include the MONOVIAL.RTM. line of drug delivery devices manufactured and sold by Becton Dickinson Pharmaceutical Systems of Le Pont de Claix, France and exemplified, for instance, by U.S. Pat. No. 5,358,501. While forming an excellent drug reconstitution system displaying superior properties, particularly convenience of use and sterility maintenance of the drug held in the vial, as typically configured these systems are useful for vial applications where the vial is of a relatively large size, typically 12 milliliters ("ml") or more. Accordingly, some pharmaceutical companies have expressed the desire for a reconstitution approach wgee the vial is of a size smaller than the sizes for which the aforementioned system is normally configured.
In response to the aforementioned concerns, then, one logical way around the dilemma would be to convert, as exactly as possible, the characteristics associated with vial components already in use by the pharmaceutical companies, such as ISO standard vial/stopper/aluminium crimp cap components, and to implement a reconstitution system around these components for use by the healthcare worker. The prior art has considered some attempts in that regard. For instance, as exemplified by PCT Patent Application No. WO 97/10156 to Biodome, SA of Issoire Cedex, France, the aluminum crimp cap which would normally hermetically affix the planar portion of the standard stopper to the vial rim is replaced by a rubber-piercing fluid transfer assembly affixed around the neck of the vial. This rubber piercing fluid transfer assembly is activated by an end user when it is desired to reconstitute the drug held in the vial. The transfer assembly disclosed in this patent application features a fairly rigid, outermost plastic locking ring which, in theory, should lock the plastic transfer assembly firmly against the planar portion of the stopper and, hence, sealing this portion stopper against the vial rim. As has been pointed out, though, in practice, there may be significant variance between the dimensional tolerances of the glass components (the vial), the rubber components (the stopper) and the plastic components (the fluid transfer assembly) forming the system. The malleable nature of the aluminum crimp cap takes into account differences in tolerances. However, owing to the rigid characteristics of the sealing ring, with this approach, there may be the possibility that given a particular vial, stopper, or transfer assembly, the sealing forces realized by the outside sealing ring against the stopper and the vial may not be sufficient or otherwise uniform. Accordingly, the potential contamination of the drug, given the environmental stresses to which the vial may be subject to during manufacture, shipping, or storage, presents a concern.
Accordingly, there is a need for a safe and effective drug reconstitution system, wherein a fluid transfer assembly is affixed to a standard vial and stopper arrangement in a manner such that the sealing forces achievable by an aluminum crimp cap are effectively replicated. Such a drug reconstitution system is disclosed herein.